The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 21, 1995
Filed:
Dec. 21, 1992
Applicant:
Inventor:
Robert K Galpin, Chippenham, GB;
Assignee:
GPT Limited, , GB;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04M / ; H04M / ; H04M / ; H04J / ;
U.S. Cl.
CPC ...
379-2 ; 379-5 ; 379 27 ; 379 29 ; 379 30 ; 370 13 ; 370 15 ;
Abstract
There is a demand for user access to ISDN services at the two-wire interface point. The frequently raised objection to such access is the problem of determining the location of a fault and hence the responsibility for the fault. This is solved by the use of a voltage sensor responsive to a DC voltage less than a normal line feed voltage within a voltage range not used in normal operation to control a switch operative to disconnect a subscriber termination unit from the line, and to provide a known linear terminating impedance for the line for the duration of the application of the DC voltage.